The present invention relates generally to integrated circuit fuse structures, and more particularly to methods and systems for testing integrated circuit fuse element structure.
Electrical fuses, particularly silicided and non-silicided polysilicon fuses, have been widely adopted in integrated circuit fabrication over conventional metal fuses because of their package level reparability, field programming abilities, and built in self-test/self-repair abilities. Fuse elements are commonly utilized in field programmable, custom logic integrated circuits, such as programmable read-only memory (PROM) and programmable logic array circuits.
In the case of silicided polysilicon fuse elements, programming occurs by applying a voltage or current stress that results in a temperature high enough to cause agglomeration of the silicided layer. Little is known, however, about the thermal gradient or behavior of the fuse element with respect to its integrated circuit environment during programming. Currently, the thermal effect of programming cannot be understood without time consuming and extensive physical examinations, such as top view SEM (scanning electron microscopy) and cross-sectional SEM/TEM (transmission electron microscopy) analysis.
Therefore, a new method and system of determining the thermal behavior of a fuse element during programming are desired.
A method of monitoring heat dissipation behavior of a fuse element formed in an integrated circuit structure is provided. A fuse element is fabricated in an integrated circuit structure. A plurality of resistors are formed adjacent the fuse element, wherein a resistivity of the resistors is temperature dependent. The fuse element is triggered, whereby heat is dissipated into the integrated circuit structure. A resistance change in the resistors is monitored to determine the heat dissipation behavior of the fuse element during triggering.
A fuse element testing system is also provided. The system includes an integrated circuit test structure including a fuse element formed over a semiconductor substrate and a plurality of resistors formed adjacent to the fuse element, wherein a resistivity of the fuse element is temperature dependent. The system also includes means for monitoring a resistance change in the resistors to determine a heat dissipation behavior of the fuse element during triggering.
The above and other features of the present invention will be better understood from the following detailed description of the preferred embodiments of the invention that is provided in connection with the accompanying drawings.